FIG. 2 shows one exemplary configuration of a magneto-optical recording/reproduction device which is one of prior known optical record/playback devices. Laser light emitted from a laser 311 mounted on an optical head 3 is collimated by a collimator lens 312 into parallel rays of light, which are guided via a beam splitter 324 to a lens 321 that forms a light spot 21 on a magnetooptical recording medium 8. The position of the light spot 21 on the magnetooptical recording medium 8 is controllable by movement of the lens 321 and optical head 3 under control of an optical spot scan control means 63. Reflection light from the magnetooptical recording medium 8 is guided by the beam splitter 324 toward a photodetector means 33. A reproduction signal from the photodetector 33 is processed by a reproduction circuit 93 for conversion to reproduction data. These overall reproduction operations are under control of a controller 55.
As a method for reproducing information as recorded in high density using the optical record/reproduction device, a magnetic super-resolution reproduction method is proposed in, for example, Published Unexamined Japanese Patent Application Nos. 3-93058 and 3-93056, which method utilizes a temperature increase within a light spot during reproduction to reconstruct information corresponding to such temperature increase part, or to reproduce information of those portions other than the temperature increased part in the spot.
In this case, certain light of substantially constant intensity was continuously irradiated as the reproduction light. Alternatively, as disclosed in JP-A-56-37834, pulsed light was irradiated at extra high frequencies. With such an arrangement, however, the pulsed light irradiation is effectively equivalent to continuous light irradiation because of the fact that the repeat frequency of such pulses is as high as several hundreds of megahertz or greater so that both the temperature on the recording medium and a reproduction output obtainable from reflection light are hardly responsive to a reproduction output of the pulsed light.